Sound-reproducing machine



Patented Mar. 6, 1928.

ENT OFFICE.

WILLIAM H. THOMMEN, OF PLYMOUTH, WISCONSIN.

SOUND-REPRODUCING MACHINE. I

Application filed December 3, 1920. Serial No. 429,323.

This invention relates in general to improvements in the art of reproducing sound and of amplifying sound waves, and relates more specifically to improvements in the I construction and operation of sound reproducingmachines such as phonographs which are adapted to reproduce sounds simulating the human voice, instrumental music and the like.

A general object of the invention is.to provide a sound reproducing machine which is relatively simple in construction and efficient in operation.

Several of the more important specific ohjects of the invention are as follows accessible for inspection, manipulation and removal.

To provide a cabinet phonograph which has unimpaired utility as an article of furniture, and which presents a neatand pleasing appearance.

To provide an improved reproducing mechanism for phonographs, which may be readily applied to existing instruments or cabinets.

To provide other improvements in construction and operation of sound reproducing machines, which will reduce to a minimum the cost of manufacture, and which will enhance to a maximum the efiiciency of operation.

Some of the novel features of construc tion of sound reproducing machines, disclosedbut not specifically claimed herein, form the subject of a copending applica tion for patent, bearing Serial No. 413,111. filed September 27, 1920.

- A clear conception of an embodiment of the invention and-of the operation of a mechanism constructed in accordance, therewith, maybe had by referringto the drawing accom this speci catlon, in which like reference characters designate the same or similar parts in the various views. a

Fig. 1 is a side elevation, partly in section, of an improved sound reproducing machine of the cabinet type.

Fig. 2 is a front view of animproved sound reproducing machine of the cabinet type, the upper front door having been omitted therefrom in order to more clearly disclose the reproducing mechanism.

Fig. 3 is a transverse horizontal section through an improved sound reproducing machine of the cabinet type, the section being taken along the line IIIIII of Fig. 1, looking in a downward direct-ion. V

The specific sound reproducing machine illustrated in the drawing, comprises in genoral a cabinet or casing 10 having a horizontal motor board 17 therein dividing the casing into upper and lower chambers, sound reproducing mechanism located within the casing above the motor board 17, a motor for actuating the reproducing mechanism located directly below the motor board 17, a final amplifying and distributing chamber 8 located above the motor board 17 and in direct proximity to the sound reproducing mechanism, and a record storage chamber located within the lower portion of the casing 10 below the driving motor. The cabinet 10 has four rigidly united corner posts 11 to the upper extremities of which the horizontal cabinet top 12 is immovablysecured, and the lower extremities of which serve as supporting legs for the cabinet. The lower side walls, back and bottom of the cabinet 10 are also immovably attached to the ,posts 11 and to the motor board 17,

The actuating motor not shown, is ordinarily hung from the motor board 17 and ishoused Within a supplementary compartment above the record storage chamber. The driving or actuating motor may be of any suitable type such as a spring motor capable of being energized by means of a rotary crank 15 at the side of the cabinet 10, and is adapted to deliver rotary motion upwardly through the motor board 17 by virtue of a vertical main spindle 14. Access to the actuating motor and to the record storage chamber located adjacent thereto, may be had through a front ,door 16.

The sound reproducing mechanism conanying and forming a part of Ill sists generally of a rotary horizontal turn table 2 detachably mounted upon the upper extremity of the driving spindle 14 and adapted to support diso records 4, a reproducer 3 having a stylus and needle coactable with a spiral recording groove formed upon the record 4, and a horizontal- ]y oscillatory tone and amplifying arm 5 movable to and fro over the record t and having the reproduccr 3 pivotally attached to its overhanging end. The oscillatory sound amplifying arm 5 is swingingly supported by a pivot bearing (3 mounted upon the motor board 17 to the rear of the turn table 2. and has a gradually enlarging interior sound amplifying passage the smaller end of which communicates with the reproducer 3 and the larger trumpet-shaped end or opening 18 of which opens upwardly directly into the final annilifying and distributing chamber 8 substantially in line with the axis of the bearing 6. The bearing 6 is preferably of an anti-friction type such as a ball bearing. and means may he provided for counter-balaiu-ing the weight of the overhanging end of the arm The amplifying arm 5 is preferably formed of wood or molded material but may be constructed of metal. The larger end or upwardly extending delivery opening 18 of the amplifying arm 5 is directed toward the lower surface of a distributing wall 13 lo cated directly above the final amplifying and distributing chamber 8. The final amplifying and distributing chamber 8 extends forwardly and laterally over and in direct proximity to the sound reproducing mechanism, this chamber 8 also preferably having gradually enlarging cross-sectional area approaching its discharge or delivery openings.

The bottom of the combined final amplifying and reproducer mechanism housing chamber 8 is bounded by the motor board 17 while the top and rear thereof are bounded by the stationary sound distributing walls having three gradually curved upwardly inclined surfaces 13, 23 extending forwardly and laterally relatively to the delivery opening 18 of the amplifying arm 5. The lower rear extremities of these sound guiding and distributing surfaces 13, -23 meet in proximity to the larger end of the swingable arm 5 to form a distributor adapted to distribute the sound toward the front and sides of the casing 10. The final amplifying and distributing chamber 8 has a front and two side delivery openings which communicate directly with openings in the front grille or upper door 7 and in the opposite side grilles or upper doors 9. respectively. These grille openings may be covered with fine mesh fabric for preventing dust from entering and accumulating inthe chamber 8. The grilles 7, 9 may be made freely removable in order to permit ready access to all portions of the chamber 8 for manipulation, inspection or removal of the mechanism therein, and also in order to permit free delivery of the sound waves from the chamber 8 in any desired direction or in several directions.

During normal operation of the sound reproducing machine. a disc record t is positioned upon the turn table 2, the reproduccr :l and amplifying arm 5 are positioned as shown in the drawin and the operating motor is set in motion to impart rotation to the record t and turn table 2 through the vertical main spindle 14-. As the record 4 rotates, the needle of the reproducer 8 is vibrated by undulations on the record thread, such vibration of the needle being imparted to the rcproducer diaphragn'i which produces and delivers condensed sound waves into the smaller end of the an'iplifying arm passage. As these condensed sound waves advance through the gradually enlarging passage of the arm 5, they aregradually and effectively amplified being finally delivered in substantially completely amplified form, from the delivery opening 18 of the arm 5. The initially amplified sound waves discharged upwardly into the chamber 8, strike the distributing surfaces 13, 23 of the top walls and have their direction of travel changed from vertical to substantially horizontal. The sound waves then advance for 'ardly and laterally through the final amplifying chamber 8, being eventually delivered in fully amplified form. from the casing 10 past the grilles 7, 9 or through the openings normally occupiedhy these grilles.

Due to the spiral formation of the thread or groove in the disc record 4, the amplifying arm 5 and rcprodueer 3 are gradually swung horizontally over and toward the axis of rotation of the turn table 2, until the inner end of the record thread is reached. when the driving motor may be stopped either manually or with the aid of an automatic stop. Due to the formation of the delivery opening 18 substantiallyconcentric with the pivot bearing ti and the resulting delivery of the amplified sound waves in vertical alincment with the pivot axis, oscillation of the arm 5 does not in any manner affect or change the angle or place of delivery of the amplified sound waves against the lower distributing surfaces 13, Q3. The sound waves are thus uni-' formly distributed by the surfaces 13, 23 regardless of the angular position of the arm 5 about its pivot bearing 6. While the reproducing mechanism disclosed in the drawing is of the type known in the art as lateral undulation reproducing mechanism, it must be apparent that the invention is equally capable of application to Hill machines utilizing hill and dale and other forms of reproducing mechanisms.

If it is desirable to gain access to the sound reproducing mechanism, the doors 7, 9 may be quickly removed without disturbing objects located upon the stationary top 12 of the cabinet 10. With this arrangement of elements, the top 12 may be utilized to support objects of decoration, or may be employed as a convenient support for record albums while the machine is being operated. Upon removal of the side doors 9, the amplifying arm 5 and reproducer 3 may be readily lifted away from the bearing 6 forming the supporting pivot for these elements. The record support or turn table 2 may also be freely vertically removed thus permitting free access to all portions of the distributing chamber 8 and of the mechanism located therein.

It will be noted that by properly forming the passage within the arm 5, the sound waves delivered from the reproducer 3 may be gradually and fully amplified before delivery from the upwardly directed opening 18 of the arm 5. The distributing chamber 8 serves to uniformly distribute and to finally amplify the sound waves so as to produce full and uniform' tones at the easing delivery openings. The disposition of the reproducing mechanism within the distributing chamber 8 does not undesirably affect even delicate sounds, since the sound waves are practically fully amplified within the amplifying arm 5.

By providing delivery openings from the distributing chamber 8 on three sides of the cabinet 10, the sound may be effectively dis tributed by the surfaces 13, 23 over a relatively great area. The range of distribution may be limited by tightly closing some of the grille openings and the volume of the sound may be likewise varied if so desired. The features of the invention are applicable to other forms of cabinet from that disclosed and the mechanism may readily be applied to any of the standard existing types of cabinets.

It should be understood that it is not desired to limit the invention to the exact details of construction and operation herein shown and described, for various modifications within the scope of the appended claims, may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent 1. In combination, means for producing sound waves, a movable tone arm having an upwardly directed open trumpet shaped rear delivery end, and means forming a single final amplifying and distributing chamber communicating directly with the delivery end of said tone arm, said chamber being open at the front and both sides and the top and rear of said chamber being bounded by a forwardly and two laterally and upwardly inclined intersecting surfaces for conducting sound waves delivered from said tone arm in forward and lateral directions.

2. In combination, means for producing sound waves, a movable tone arm having an upwardly directed open trumpet shaped rear delivery end, and means forming a single final amplifying and distributing chamber communicating directly with the delivery end of said tone arm, said chamher being open at the front and both sides and the top and rear of said chamber being bounded by a forwardly and two laterally and upwardly inclined intersecting surfaces for conducting sound waves delivered from said tone arm in forward and lateral direc tions, said sound wave reproducing means being freely accessible for manipulation through the front and side delivery openings of said chamber.

3. In combination, means for producing sound waves, a pivotally supported tone arm having an upwardly directed open rear delivery end concentric with the tone arm supporting pivot, and means forming a single final amplifying and distributing chamber in open communication with the delivery end of said tone arm, said chamber being open at the front and both sides and the top and rear of said chamber being bounded by a forwardly and two laterally and upwardly inclined intersecting surfaces for conducting sound waves delivered from said tone arm in forward and lateral directions.

In testimony whereof, the signature of the inventor is aflixed hereto.

WILLIAM H. THOMMEN. 

